Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds concrete idempotency semantics beyond the idempotentHint annotation: 'Insert-only: an owner already present is left untouched, so running it twice adds nothing.' It also specifies the resulting security type, and nothing in the description contradicts annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences with no filler. The core action and outcome are front-loaded, and the idempotency caveat is delivered compactly in the second sentence.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter, insert-only tool with idempotent and non-destructive annotations plus an output schema, the description covers what the tool does, how it behaves on repeat calls, and what it produces. No missing information would prevent correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the single companyId parameter is fully documented in the schema. The description adds no parameter-level detail beyond implying the relevant company, so the baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific operation ('Carries the owners named during a company's formation onto its cap table') and the exact resulting role ('as founders holding common stock'). This clearly differentiates it from generic cap table stakeholder creation tools among the siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives a clear context: use after formation to promote formation owners to cap table founders. It does not explicitly name alternatives or exclusion conditions, but the insert-only sentence clarifies behavior enough to avoid misuse, so it earns a 4 rather than a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.